Midland officials at the scene of an accident where a trailer carrying wounded veterans on a parade float was struck by a train in Midland, Texas, in Nov. / Tim Fischer, AP

by USA TODAY

by USA TODAY

MIDLAND, Texas (AP) - A grand jury on Wednesday declined to indict the driver of a float involved in a train collision that killed four U.S. military veterans in a West Texas parade.

Dale Andrew Hayden, the driver of the truck pulling the float, will not face charges stemming from the Nov. 15 accident that killed four veterans who had served in Iraq and Afghanistan. Sixteen other people were injured.

Though the 12-person grand jury did not indict Hayden, it "has not concluded its review of the incident," according to a news release issued by Midland County District Attorney Teresa Clingman. Clingman declined to comment further.

The veterans were riding on a flatbed truck that was hit by a Union Pacific train traveling at 62 mph. The truck was the second float in a parade organized to honor wounded veterans and their wives.

The accident remains under investigation by the National Transportation Safety Board.

According to the NTSB, the railroad crossing warning system was activated 20 seconds before the accident, and the guardrail began to come down seven seconds after that. Investigators say the float began crossing the train tracks even though warning bells were sounding and the crossing lights were flashing.

Omaha, Neb.-based Union Pacific Corp. announced in December that it was adjusting the timing of the crossing signal where the collision occurred.

The veterans had been invited to Midland, a transportation and commerce hub in the West Texas oilfields, for a three-day weekend of hunting and shopping in appreciation of their service. A local charity, Show of Support, organized the trip, parade and other festivities.

Show of Support officials did not get a parade permit from the city.

In the days after the crash, Hayden was placed under a physician's care and got counseling, his attorney, Hal Brockett has said.

Hayden, who has a military career spanning more than three decades, works as a truck driver for Smith Industries, an oilfield services company. The company placed Hayden on medical leave after the accident. Brockett said Hayden is back at work.